The present invention is related to the field of data and telephony communication devices.
A conventional telephone includes a keypad having ten numeric keys, each of which generates a corresponding set of tones on a telephone line to signal a corresponding decimal digit of a telephone number when pressed. This arrangement works well for telephone numbers that are expressed as strings of decimal digits. However, there has been increasing use of what can be referred to as “mnemonic” telephone numbers, i.e., telephone numbers that are expressed as strings of letters alone or letters mixed with decimal digits. For example, telephone numbers of this type are used in nationwide toll-free calling plans employing special area codes such as “800”. Many businesses purchase toll-free numbers that can be expressed using a word or phrase associated with the business or its goods or services, in order to make it easier for customers to contact the business.
The conventional telephone keypad allows for use of such mnemonic telephone numbers by simply assigning groups of three letters to each digit. Thus, the letters “A”, “B”, and “C” are assigned to the digit “2”, etc. There is no special functionality in the telephone. Rather, the letters are merely printed on each digit key. However, this set of letter-to-digit assignments is not easily remembered. A user dialing a mnemonic telephone number generally must scan the keypad multiple times during dialing, in order to find the correct key to press for each letter of the mnemonic telephone number. This process is inefficient and error-prone. It would be desirable to provide for a more efficient and error-free way of dialing mnemonic telephone numbers.